The crop tool is available in canvas.
It helps you cut what you don't want in your image and also expand your image with the help of refill.
Cropping your image
When you enable the Crop Tool (C) a settings screen will be visible on the right.
Here you can:
Set the width of the crop area
Set the height of the crop area
Fill in blank areas
When you want to extend your image, you can easily use the cropping tool and Layer will refill the empty areas magically. To refill:
Enable Crop tool with
Cor by clicking in the left toolbar section
Expand the cropping area bigger than your image.
Hit Refill in the crop options menu on the right.